Use of Bioreactors in the Leaching of an Oxidized Copper Ore

−− Copper recoveries using two methodologies of acid leaching of a low-grade ore are reported in this work. The ore, abounding in oxidized species, was from Barda González reservoir in Neuquén province, Argentina. In the first methodology, cells of Acidithiobacillus thiooxidans were inoculated into a column containing the ore and sulfur as energy source. In the second one, a bioreactor with immobilized cells of Acidithiobacillus thiooxidans placed on small pieces of elemental sulfur was used to generate acid medium. This medium was then transferred to another column containing the ore. In the first methodology low cell counts and also low copper recovery were obtained. However, in the other, about 56 % of copper was recovered after four loads of fresh medium. Keywords−− Bioreactors, copper, oxidized ore, Acidithiobacillus thiooxidans.